1. Field of the Invention
The field of the invention is broadly the modulation of certain carrier media for the purpose of transmitting information between two spatially separated points. More particularly, the invention addresses a particular method and use of pulse-width modulation (PWM) for the encoding of digital data into certain physical signals prior to transmission and the decoding of such signals back into a representation of the same digital data.
2. Discussion of the Related Art
Prior art in modulation and demodulation teaches various methods of pulse-width, amplitude, frequency, phase, polarization, and acousto-optic modulation. To achieve higher spectral efficiency, these methods are often combined to produce a physical symbol having multiply definable and measurable physical characteristics. A symbol with multiple independently controllable features may be termed multidimensional, with each physical parameter representing a distinct dimension.
A problem with conventional approaches is the requirement for multiple circuits operating in parallel to achieve distinct and separate modulation of each of the several physical attributes. This complicates both the transmitter and receiver process and hardware in that the diverse physical attributes being modulated or demodulated require distinct and separate means that must be managed simultaneously.